HVAC & IAQ
Healthy Air Must Flow
Imagine the HVAC in your facility failing ten or twenty
years ago. After the repair bill hit, a decision would be made
to avoid that cost in the future, taking operating expenses and
asset lifecycles into account. The smart people in the room
would try to weigh the human cost of discomfort due to lost
temperature and humidity control, but it’s hard without clear
numbers. A plan would be made, a consensus built, hands
shaken, and things would move forward.
Today, the handshakes may feel like signs of a simpler time,
but it is the evaluation of costs that should really concern us.
A very big risk has not been accounted for that is very clear to
us now, after the events of 2020. What
was missed?
PHOTO CREDIT ELNUR
In our imaginary building ten years
ago, there was also a significant rise in
sick days the following week. Even if
someone connected the rash of colds to
the lack of good airflow, that concern
did not make it up the chain to the
decision makers.
The truth is, building owners and
operators are very well-practiced at
accounting for the cost of repairing or replacing a failed piece
of equipment. Failed ventilation itself, on the other hand, has
many more risks that owners and operators are less practiced
at accounting for—but that should no longer be left off the
list. And while the discomfort of poor temperature control
has real impacts on performance, when the HVAC goes down,
buildings lose more than temperature control. Lack of airflow
and humidity control can both lead to increased exposure to
pollutants and pathogens.
The Cost of Poorly Maintained
Ventilation Systems
The financial impact of a pandemic event like COVID-19 may
be incalculable. Before the SARS-CoV-2 virus, however, experts
were already working hard to expand our understanding
of poor indoor air quality and educate the public about those
risks and costs. In fact, indoor air was believed to be a major
environmental factor by 1850. The fact that we spend 90% of
our time indoors is often cited to give crucial context to the
EPA’s finding that certain indoor pollutant levels were 2 to 5
times larger than the concentrations outside.
As our understanding of indoor air
quality issues has grown, ASHRAE (the
American Society of Heating, Refrigerating
and Air-Conditioning Engineers) has
set and raised standards for ventilation
to protect indoor air and the people who
breathe it. Standards help make it clear
that a poorly maintained ventilation
system can lead to a sub-standard indoor
environment, but the costs of those risks
depend on the various health impacts
studied. One study cites the annual cost of care for upper and
lower respiratory tract infections at $36 billion and the cost of
lost work at $34 billion. The same study found that 23% of office
workers reported symptoms of sick-building syndrome improved
away from their work environments—and calculates the cost of
sick-building syndrome to businesses nationwide at $60 billion.
Another way of looking at the cost of indoor air quality is the
opportunity lost: The benefits of improved indoor environments
have been calculated to be 18 to 47 times greater than the costs.
HVAC Downtime Can Be Avoided
For ventilation to remain adequate for our indoor environments,
the HVAC equipment responsible for that ventilation
simply cannot break down. HVAC systems have evolved to improve
efficiency and give us better control over environments,
and those systems have multiple components that should be
properly cared for to avoid issues—from compressors and coils
to variable-speed fans and high-efficiency filters.
Since the COVID-19 pandemic, standards organizations
ASHRAE and the CDC have both stressed the importance of increasing
ventilation to reduce pathogen counts in shared spaces.
Their recommendations include discontinuing the use of demand
controls that may reduce ventilation and increasing airflow to
spaces when occupied. Taking these steps may increase the load
on an HVAC system, and a poorly maintained system is less
equipped to stay operational and efficient under those conditions.
Guidance on increasing filtration for HVAC systems also
notes that increasing filter efficiency can lead to reduced
airflow. Compensating can increase energy use as fans and
components work harder. A poorly maintained system is also
in danger of responding inadequately to those needs.
When the System Is the Problem
A poorly maintained HVAC system can itself be a source of
indoor pollutants. Filters, air ducts, cooling coils, and drain
pans are all examples of failure points where lack of attention
can introduce unwanted contaminants.
Imagine a food safety inspector asking why a restaurant’s
kitchen is so filthy, and the owner responding, “Well, we
cleaned it when it was built.” The food we eat shouldn’t be
produced by a contaminated system, and the air we breathe shouldn’t arrive through one.
Poorly maintained cooling coils, drip pans, or cooling
towers have been found to be the cause of respiratory diseases
(like legionnaires). According to one estimate, the interior
surface area of air ducts is 10% of the floor of office spaces, and
dust accumulation there can promote the growth and release of
micro-organisms and metabolic products into the air.
Just Open a Window?
When indoor ventilation breaks down, simply opening a window
may feel like a great temporary fix. However, not every facility has
this option, and the sad truth is that exposure to outdoor air carries
risks that we’re also continuing to learn about. A Stanford-led
study from 2021 found that children’s exposure to outdoor pollutants,
even for only a single day, led to changes in gene expressions
that impacted their long-term chances of heart disease.
Limited access to outdoor air is also a problem during a
facility’s response to indoor pathogen spread. In recommendations
for reducing exposure to SARS-CoV-2, the virus that
causes COVID-19, the CDC noted that opening windows
could reduce the concentration of viral particles inside. That
recommendation is hedged with important caveats, however,
such as to use caution in highly polluted areas. In fact, the
CDC goes on to recommend, “Ensure ventilation systems
operate properly and provide acceptable indoor air quality for
the current occupancy level for each space.”
It’s Not All Downside
Studies show that improving indoor air quality has positive
effects. A 2015 study found that enhanced ventilation, including
reduction in volatile organic compounds, led to increased
cognitive performance scores and improvements in information
usage and crisis response. Enhancing ventilation may increase
an HVAC system’s load, but a well-maintained and optimized
system can help a facility deliver the benefits of improved
indoor air quality in a cost-effective manner.
The Time Is Now
Given the health risk that poor indoor air quality poses to the
people who share the air in our facilities, it may be time to consider
HVAC a mission-critical asset. The first step in improving
the indoor air quality in our facilities is ensuring that ventilation
meets or exceeds the clear guidelines for airflow. Keeping those
systems running optimally may be a cost, but when compared
to the risks of poor ventilation passed on to the people in our
facilities, the benefits of proactive maintenance are clear.
This article originally appeared in the Spring 2021 issue of Spaces4Learning.